Interlaced video artefacts

Interlaced video artefacts

Hi,

I'm encoding an interlaced video sequence using the MFX h264 encoder (mfx.FrameInfo.PicStruct=MFX_PICSTRUCT_FIELD_TFF), when I enabled the B slices some blocks artefacts appears when playing the video sequence, those artefacts disappears by removing disabling B slices or by encoding in progressive mode (mfx.FrameInfo.PicStruct=MFX_PICSTRUCT_PROGRESSIVE).

Do you have any idea how to fixe this issue?

Best regards

Abdellatif KHINDOUF

 

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Hi,

Could you please share some information about your system configuration. If you like you can use the "mediasdk_sys_analyzer" tool part of the SDK to dump system config info.

Could you also please provide a Media SDK trace log captured for your workload. The tool is part of the SDK package, Please also make sure to turn on per frame logging before capturing the trace.

Regards,
Petter

Hi,

Please find attached the two requested files; I hop that this will help you to understand this issue.

Regards,

Abdellatif

Attachments: 

Hi Abdellatif,

I replicated your exact configuration locally (using the same driver), based on the trace log you provided, but do not observe any issues.
Do you see the issue if you make modifications to sample_encode to enforce the same config or just with your own application?

Your system configuration looks fine, and I can see you use a recent driver.

Could you share encoded stream which showcases artifacts.

Regards,
Petter

Hi Petter,

I don't think I can reproduce this issue with sample_encode, I guess it's revealed when we use simultaneously (in the same stream) frames and fields pictures with B frames.
I attached the resulting bitstream, you can see the issue at picture=53 (display order).

Regards,

Abdellatif

Attachments: 

AttachmentSize
Downloadapplication/zip block.zip706.84 KB

Hi,
I see the artifact you refer to and understand the use case you're pursuing.

To be able to reproduce the issue locally, would you be able to provide the raw input content and exact frame configuration you're trying to achieve, such as frame 1: TFF, frame 2: progressive. etc.

Regards,
Petter

Hi,

Please find attached the:
- YUV source file "src.zip", it's 720x576@25fps.
- H264 file "es.zip" at 1.5Mbps

Here are the encoding parameters (frame number is in display order):
- GOP=40 with 2B frames
- frame 0 to frame 19: progressive
- frame 20 to frame 22: TFF
- frame 23 to frame 28: progressive
- frame 29 to frame 36: TFF
- frame 37: progressive
- frame 38 to frame 40: TFF

You can use a tool like http://www.elecard.com/en/products/professional/analysis/streameye.html to see more detailed information.

I hop that this will help you to reproduce this issue.

Regards,

Abdellatif

Attachments: 

AttachmentSize
Downloadapplication/zip src.zip12.53 MB
Downloadapplication/zip es.zip419.46 KB

Hi Abdellatif,

I was able to reproduce the issue using the information you provided. Thanks for reporting your findings!
We are currently classifying this as a bug, and the issue will be investigated further.

Regards,
Petter

Hi Abdellatif,

I've got an update on this issue. Unfortunately it's not very good news.

We will not be able to fix the issue for the current Intel Core platforms and driver. Instead, a resolution to this is planned for the next generation Core platform.

I hope you will be able to find a suitable workaround that will not limit your targeted use cases too much.

Regards,
Petter

Petter,
Is there a place where developers can find and review errata/bugs like this related to Quick Sync?

Thanks,
Cameron

Hi Cameron,

Your request is very valid.

Unfortunately there is not a complete external list of known bugs related to Intel QuickSync available. We are working with the Intel Graphics driver team to improve the transparency in this area.

Regards,
Petter

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